| // Copyright 2011 the V8 project authors. All rights reserved. |
| // Redistribution and use in source and binary forms, with or without |
| // modification, are permitted provided that the following conditions are |
| // met: |
| // |
| // * Redistributions of source code must retain the above copyright |
| // notice, this list of conditions and the following disclaimer. |
| // * Redistributions in binary form must reproduce the above |
| // copyright notice, this list of conditions and the following |
| // disclaimer in the documentation and/or other materials provided |
| // with the distribution. |
| // * Neither the name of Google Inc. nor the names of its |
| // contributors may be used to endorse or promote products derived |
| // from this software without specific prior written permission. |
| // |
| // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
| // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
| // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
| // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
| // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| |
| #ifndef V8_CONVERSIONS_INL_H_ |
| #define V8_CONVERSIONS_INL_H_ |
| |
| #include <limits.h> // Required for INT_MAX etc. |
| #include <math.h> |
| #include <float.h> // Required for DBL_MAX and on Win32 for finite() |
| #include <stdarg.h> |
| #include "globals.h" // Required for V8_INFINITY |
| |
| // ---------------------------------------------------------------------------- |
| // Extra POSIX/ANSI functions for Win32/MSVC. |
| |
| #include "conversions.h" |
| #include "double.h" |
| #include "platform.h" |
| #include "scanner.h" |
| #include "strtod.h" |
| |
| namespace v8 { |
| namespace internal { |
| |
| inline double JunkStringValue() { |
| return BitCast<double, uint64_t>(kQuietNaNMask); |
| } |
| |
| |
| inline double SignedZero(bool negative) { |
| return negative ? uint64_to_double(Double::kSignMask) : 0.0; |
| } |
| |
| |
| // The fast double-to-unsigned-int conversion routine does not guarantee |
| // rounding towards zero, or any reasonable value if the argument is larger |
| // than what fits in an unsigned 32-bit integer. |
| inline unsigned int FastD2UI(double x) { |
| // There is no unsigned version of lrint, so there is no fast path |
| // in this function as there is in FastD2I. Using lrint doesn't work |
| // for values of 2^31 and above. |
| |
| // Convert "small enough" doubles to uint32_t by fixing the 32 |
| // least significant non-fractional bits in the low 32 bits of the |
| // double, and reading them from there. |
| const double k2Pow52 = 4503599627370496.0; |
| bool negative = x < 0; |
| if (negative) { |
| x = -x; |
| } |
| if (x < k2Pow52) { |
| x += k2Pow52; |
| uint32_t result; |
| Address mantissa_ptr = reinterpret_cast<Address>(&x); |
| // Copy least significant 32 bits of mantissa. |
| memcpy(&result, mantissa_ptr, sizeof(result)); |
| return negative ? ~result + 1 : result; |
| } |
| // Large number (outside uint32 range), Infinity or NaN. |
| return 0x80000000u; // Return integer indefinite. |
| } |
| |
| |
| inline double DoubleToInteger(double x) { |
| if (isnan(x)) return 0; |
| if (!isfinite(x) || x == 0) return x; |
| return (x >= 0) ? floor(x) : ceil(x); |
| } |
| |
| |
| int32_t DoubleToInt32(double x) { |
| int32_t i = FastD2I(x); |
| if (FastI2D(i) == x) return i; |
| Double d(x); |
| int exponent = d.Exponent(); |
| if (exponent < 0) { |
| if (exponent <= -Double::kSignificandSize) return 0; |
| return d.Sign() * static_cast<int32_t>(d.Significand() >> -exponent); |
| } else { |
| if (exponent > 31) return 0; |
| return d.Sign() * static_cast<int32_t>(d.Significand() << exponent); |
| } |
| } |
| |
| |
| template <class Iterator, class EndMark> |
| bool SubStringEquals(Iterator* current, |
| EndMark end, |
| const char* substring) { |
| ASSERT(**current == *substring); |
| for (substring++; *substring != '\0'; substring++) { |
| ++*current; |
| if (*current == end || **current != *substring) return false; |
| } |
| ++*current; |
| return true; |
| } |
| |
| |
| // Returns true if a nonspace character has been found and false if the |
| // end was been reached before finding a nonspace character. |
| template <class Iterator, class EndMark> |
| inline bool AdvanceToNonspace(UnicodeCache* unicode_cache, |
| Iterator* current, |
| EndMark end) { |
| while (*current != end) { |
| if (!unicode_cache->IsWhiteSpace(**current)) return true; |
| ++*current; |
| } |
| return false; |
| } |
| |
| |
| // Parsing integers with radix 2, 4, 8, 16, 32. Assumes current != end. |
| template <int radix_log_2, class Iterator, class EndMark> |
| double InternalStringToIntDouble(UnicodeCache* unicode_cache, |
| Iterator current, |
| EndMark end, |
| bool negative, |
| bool allow_trailing_junk) { |
| ASSERT(current != end); |
| |
| // Skip leading 0s. |
| while (*current == '0') { |
| ++current; |
| if (current == end) return SignedZero(negative); |
| } |
| |
| int64_t number = 0; |
| int exponent = 0; |
| const int radix = (1 << radix_log_2); |
| |
| do { |
| int digit; |
| if (*current >= '0' && *current <= '9' && *current < '0' + radix) { |
| digit = static_cast<char>(*current) - '0'; |
| } else if (radix > 10 && *current >= 'a' && *current < 'a' + radix - 10) { |
| digit = static_cast<char>(*current) - 'a' + 10; |
| } else if (radix > 10 && *current >= 'A' && *current < 'A' + radix - 10) { |
| digit = static_cast<char>(*current) - 'A' + 10; |
| } else { |
| if (allow_trailing_junk || |
| !AdvanceToNonspace(unicode_cache, ¤t, end)) { |
| break; |
| } else { |
| return JunkStringValue(); |
| } |
| } |
| |
| number = number * radix + digit; |
| int overflow = static_cast<int>(number >> 53); |
| if (overflow != 0) { |
| // Overflow occurred. Need to determine which direction to round the |
| // result. |
| int overflow_bits_count = 1; |
| while (overflow > 1) { |
| overflow_bits_count++; |
| overflow >>= 1; |
| } |
| |
| int dropped_bits_mask = ((1 << overflow_bits_count) - 1); |
| int dropped_bits = static_cast<int>(number) & dropped_bits_mask; |
| number >>= overflow_bits_count; |
| exponent = overflow_bits_count; |
| |
| bool zero_tail = true; |
| while (true) { |
| ++current; |
| if (current == end || !isDigit(*current, radix)) break; |
| zero_tail = zero_tail && *current == '0'; |
| exponent += radix_log_2; |
| } |
| |
| if (!allow_trailing_junk && |
| AdvanceToNonspace(unicode_cache, ¤t, end)) { |
| return JunkStringValue(); |
| } |
| |
| int middle_value = (1 << (overflow_bits_count - 1)); |
| if (dropped_bits > middle_value) { |
| number++; // Rounding up. |
| } else if (dropped_bits == middle_value) { |
| // Rounding to even to consistency with decimals: half-way case rounds |
| // up if significant part is odd and down otherwise. |
| if ((number & 1) != 0 || !zero_tail) { |
| number++; // Rounding up. |
| } |
| } |
| |
| // Rounding up may cause overflow. |
| if ((number & (static_cast<int64_t>(1) << 53)) != 0) { |
| exponent++; |
| number >>= 1; |
| } |
| break; |
| } |
| ++current; |
| } while (current != end); |
| |
| ASSERT(number < ((int64_t)1 << 53)); |
| ASSERT(static_cast<int64_t>(static_cast<double>(number)) == number); |
| |
| if (exponent == 0) { |
| if (negative) { |
| if (number == 0) return -0.0; |
| number = -number; |
| } |
| return static_cast<double>(number); |
| } |
| |
| ASSERT(number != 0); |
| return ldexp(static_cast<double>(negative ? -number : number), exponent); |
| } |
| |
| |
| template <class Iterator, class EndMark> |
| double InternalStringToInt(UnicodeCache* unicode_cache, |
| Iterator current, |
| EndMark end, |
| int radix) { |
| const bool allow_trailing_junk = true; |
| const double empty_string_val = JunkStringValue(); |
| |
| if (!AdvanceToNonspace(unicode_cache, ¤t, end)) { |
| return empty_string_val; |
| } |
| |
| bool negative = false; |
| bool leading_zero = false; |
| |
| if (*current == '+') { |
| // Ignore leading sign; skip following spaces. |
| ++current; |
| if (current == end) { |
| return JunkStringValue(); |
| } |
| } else if (*current == '-') { |
| ++current; |
| if (current == end) { |
| return JunkStringValue(); |
| } |
| negative = true; |
| } |
| |
| if (radix == 0) { |
| // Radix detection. |
| radix = 10; |
| if (*current == '0') { |
| ++current; |
| if (current == end) return SignedZero(negative); |
| if (*current == 'x' || *current == 'X') { |
| radix = 16; |
| ++current; |
| if (current == end) return JunkStringValue(); |
| } else { |
| leading_zero = true; |
| } |
| } |
| } else if (radix == 16) { |
| if (*current == '0') { |
| // Allow "0x" prefix. |
| ++current; |
| if (current == end) return SignedZero(negative); |
| if (*current == 'x' || *current == 'X') { |
| ++current; |
| if (current == end) return JunkStringValue(); |
| } else { |
| leading_zero = true; |
| } |
| } |
| } |
| |
| if (radix < 2 || radix > 36) return JunkStringValue(); |
| |
| // Skip leading zeros. |
| while (*current == '0') { |
| leading_zero = true; |
| ++current; |
| if (current == end) return SignedZero(negative); |
| } |
| |
| if (!leading_zero && !isDigit(*current, radix)) { |
| return JunkStringValue(); |
| } |
| |
| if (IsPowerOf2(radix)) { |
| switch (radix) { |
| case 2: |
| return InternalStringToIntDouble<1>( |
| unicode_cache, current, end, negative, allow_trailing_junk); |
| case 4: |
| return InternalStringToIntDouble<2>( |
| unicode_cache, current, end, negative, allow_trailing_junk); |
| case 8: |
| return InternalStringToIntDouble<3>( |
| unicode_cache, current, end, negative, allow_trailing_junk); |
| |
| case 16: |
| return InternalStringToIntDouble<4>( |
| unicode_cache, current, end, negative, allow_trailing_junk); |
| |
| case 32: |
| return InternalStringToIntDouble<5>( |
| unicode_cache, current, end, negative, allow_trailing_junk); |
| default: |
| UNREACHABLE(); |
| } |
| } |
| |
| if (radix == 10) { |
| // Parsing with strtod. |
| const int kMaxSignificantDigits = 309; // Doubles are less than 1.8e308. |
| // The buffer may contain up to kMaxSignificantDigits + 1 digits and a zero |
| // end. |
| const int kBufferSize = kMaxSignificantDigits + 2; |
| char buffer[kBufferSize]; |
| int buffer_pos = 0; |
| while (*current >= '0' && *current <= '9') { |
| if (buffer_pos <= kMaxSignificantDigits) { |
| // If the number has more than kMaxSignificantDigits it will be parsed |
| // as infinity. |
| ASSERT(buffer_pos < kBufferSize); |
| buffer[buffer_pos++] = static_cast<char>(*current); |
| } |
| ++current; |
| if (current == end) break; |
| } |
| |
| if (!allow_trailing_junk && |
| AdvanceToNonspace(unicode_cache, ¤t, end)) { |
| return JunkStringValue(); |
| } |
| |
| ASSERT(buffer_pos < kBufferSize); |
| buffer[buffer_pos] = '\0'; |
| Vector<const char> buffer_vector(buffer, buffer_pos); |
| return negative ? -Strtod(buffer_vector, 0) : Strtod(buffer_vector, 0); |
| } |
| |
| // The following code causes accumulating rounding error for numbers greater |
| // than ~2^56. It's explicitly allowed in the spec: "if R is not 2, 4, 8, 10, |
| // 16, or 32, then mathInt may be an implementation-dependent approximation to |
| // the mathematical integer value" (15.1.2.2). |
| |
| int lim_0 = '0' + (radix < 10 ? radix : 10); |
| int lim_a = 'a' + (radix - 10); |
| int lim_A = 'A' + (radix - 10); |
| |
| // NOTE: The code for computing the value may seem a bit complex at |
| // first glance. It is structured to use 32-bit multiply-and-add |
| // loops as long as possible to avoid loosing precision. |
| |
| double v = 0.0; |
| bool done = false; |
| do { |
| // Parse the longest part of the string starting at index j |
| // possible while keeping the multiplier, and thus the part |
| // itself, within 32 bits. |
| unsigned int part = 0, multiplier = 1; |
| while (true) { |
| int d; |
| if (*current >= '0' && *current < lim_0) { |
| d = *current - '0'; |
| } else if (*current >= 'a' && *current < lim_a) { |
| d = *current - 'a' + 10; |
| } else if (*current >= 'A' && *current < lim_A) { |
| d = *current - 'A' + 10; |
| } else { |
| done = true; |
| break; |
| } |
| |
| // Update the value of the part as long as the multiplier fits |
| // in 32 bits. When we can't guarantee that the next iteration |
| // will not overflow the multiplier, we stop parsing the part |
| // by leaving the loop. |
| const unsigned int kMaximumMultiplier = 0xffffffffU / 36; |
| uint32_t m = multiplier * radix; |
| if (m > kMaximumMultiplier) break; |
| part = part * radix + d; |
| multiplier = m; |
| ASSERT(multiplier > part); |
| |
| ++current; |
| if (current == end) { |
| done = true; |
| break; |
| } |
| } |
| |
| // Update the value and skip the part in the string. |
| v = v * multiplier + part; |
| } while (!done); |
| |
| if (!allow_trailing_junk && |
| AdvanceToNonspace(unicode_cache, ¤t, end)) { |
| return JunkStringValue(); |
| } |
| |
| return negative ? -v : v; |
| } |
| |
| |
| // Converts a string to a double value. Assumes the Iterator supports |
| // the following operations: |
| // 1. current == end (other ops are not allowed), current != end. |
| // 2. *current - gets the current character in the sequence. |
| // 3. ++current (advances the position). |
| template <class Iterator, class EndMark> |
| double InternalStringToDouble(UnicodeCache* unicode_cache, |
| Iterator current, |
| EndMark end, |
| int flags, |
| double empty_string_val) { |
| // To make sure that iterator dereferencing is valid the following |
| // convention is used: |
| // 1. Each '++current' statement is followed by check for equality to 'end'. |
| // 2. If AdvanceToNonspace returned false then current == end. |
| // 3. If 'current' becomes be equal to 'end' the function returns or goes to |
| // 'parsing_done'. |
| // 4. 'current' is not dereferenced after the 'parsing_done' label. |
| // 5. Code before 'parsing_done' may rely on 'current != end'. |
| if (!AdvanceToNonspace(unicode_cache, ¤t, end)) { |
| return empty_string_val; |
| } |
| |
| const bool allow_trailing_junk = (flags & ALLOW_TRAILING_JUNK) != 0; |
| |
| // The longest form of simplified number is: "-<significant digits>'.1eXXX\0". |
| const int kBufferSize = kMaxSignificantDigits + 10; |
| char buffer[kBufferSize]; // NOLINT: size is known at compile time. |
| int buffer_pos = 0; |
| |
| // Exponent will be adjusted if insignificant digits of the integer part |
| // or insignificant leading zeros of the fractional part are dropped. |
| int exponent = 0; |
| int significant_digits = 0; |
| int insignificant_digits = 0; |
| bool nonzero_digit_dropped = false; |
| |
| enum Sign { |
| NONE, |
| NEGATIVE, |
| POSITIVE |
| }; |
| |
| Sign sign = NONE; |
| |
| if (*current == '+') { |
| // Ignore leading sign. |
| ++current; |
| if (current == end) return JunkStringValue(); |
| sign = POSITIVE; |
| } else if (*current == '-') { |
| ++current; |
| if (current == end) return JunkStringValue(); |
| sign = NEGATIVE; |
| } |
| |
| static const char kInfinitySymbol[] = "Infinity"; |
| if (*current == kInfinitySymbol[0]) { |
| if (!SubStringEquals(¤t, end, kInfinitySymbol)) { |
| return JunkStringValue(); |
| } |
| |
| if (!allow_trailing_junk && |
| AdvanceToNonspace(unicode_cache, ¤t, end)) { |
| return JunkStringValue(); |
| } |
| |
| ASSERT(buffer_pos == 0); |
| return (sign == NEGATIVE) ? -V8_INFINITY : V8_INFINITY; |
| } |
| |
| bool leading_zero = false; |
| if (*current == '0') { |
| ++current; |
| if (current == end) return SignedZero(sign == NEGATIVE); |
| |
| leading_zero = true; |
| |
| // It could be hexadecimal value. |
| if ((flags & ALLOW_HEX) && (*current == 'x' || *current == 'X')) { |
| ++current; |
| if (current == end || !isDigit(*current, 16) || sign != NONE) { |
| return JunkStringValue(); // "0x". |
| } |
| |
| return InternalStringToIntDouble<4>(unicode_cache, |
| current, |
| end, |
| false, |
| allow_trailing_junk); |
| } |
| |
| // Ignore leading zeros in the integer part. |
| while (*current == '0') { |
| ++current; |
| if (current == end) return SignedZero(sign == NEGATIVE); |
| } |
| } |
| |
| bool octal = leading_zero && (flags & ALLOW_OCTALS) != 0; |
| |
| // Copy significant digits of the integer part (if any) to the buffer. |
| while (*current >= '0' && *current <= '9') { |
| if (significant_digits < kMaxSignificantDigits) { |
| ASSERT(buffer_pos < kBufferSize); |
| buffer[buffer_pos++] = static_cast<char>(*current); |
| significant_digits++; |
| // Will later check if it's an octal in the buffer. |
| } else { |
| insignificant_digits++; // Move the digit into the exponential part. |
| nonzero_digit_dropped = nonzero_digit_dropped || *current != '0'; |
| } |
| octal = octal && *current < '8'; |
| ++current; |
| if (current == end) goto parsing_done; |
| } |
| |
| if (significant_digits == 0) { |
| octal = false; |
| } |
| |
| if (*current == '.') { |
| if (octal && !allow_trailing_junk) return JunkStringValue(); |
| if (octal) goto parsing_done; |
| |
| ++current; |
| if (current == end) { |
| if (significant_digits == 0 && !leading_zero) { |
| return JunkStringValue(); |
| } else { |
| goto parsing_done; |
| } |
| } |
| |
| if (significant_digits == 0) { |
| // octal = false; |
| // Integer part consists of 0 or is absent. Significant digits start after |
| // leading zeros (if any). |
| while (*current == '0') { |
| ++current; |
| if (current == end) return SignedZero(sign == NEGATIVE); |
| exponent--; // Move this 0 into the exponent. |
| } |
| } |
| |
| // There is a fractional part. We don't emit a '.', but adjust the exponent |
| // instead. |
| while (*current >= '0' && *current <= '9') { |
| if (significant_digits < kMaxSignificantDigits) { |
| ASSERT(buffer_pos < kBufferSize); |
| buffer[buffer_pos++] = static_cast<char>(*current); |
| significant_digits++; |
| exponent--; |
| } else { |
| // Ignore insignificant digits in the fractional part. |
| nonzero_digit_dropped = nonzero_digit_dropped || *current != '0'; |
| } |
| ++current; |
| if (current == end) goto parsing_done; |
| } |
| } |
| |
| if (!leading_zero && exponent == 0 && significant_digits == 0) { |
| // If leading_zeros is true then the string contains zeros. |
| // If exponent < 0 then string was [+-]\.0*... |
| // If significant_digits != 0 the string is not equal to 0. |
| // Otherwise there are no digits in the string. |
| return JunkStringValue(); |
| } |
| |
| // Parse exponential part. |
| if (*current == 'e' || *current == 'E') { |
| if (octal) return JunkStringValue(); |
| ++current; |
| if (current == end) { |
| if (allow_trailing_junk) { |
| goto parsing_done; |
| } else { |
| return JunkStringValue(); |
| } |
| } |
| char sign = '+'; |
| if (*current == '+' || *current == '-') { |
| sign = static_cast<char>(*current); |
| ++current; |
| if (current == end) { |
| if (allow_trailing_junk) { |
| goto parsing_done; |
| } else { |
| return JunkStringValue(); |
| } |
| } |
| } |
| |
| if (current == end || *current < '0' || *current > '9') { |
| if (allow_trailing_junk) { |
| goto parsing_done; |
| } else { |
| return JunkStringValue(); |
| } |
| } |
| |
| const int max_exponent = INT_MAX / 2; |
| ASSERT(-max_exponent / 2 <= exponent && exponent <= max_exponent / 2); |
| int num = 0; |
| do { |
| // Check overflow. |
| int digit = *current - '0'; |
| if (num >= max_exponent / 10 |
| && !(num == max_exponent / 10 && digit <= max_exponent % 10)) { |
| num = max_exponent; |
| } else { |
| num = num * 10 + digit; |
| } |
| ++current; |
| } while (current != end && *current >= '0' && *current <= '9'); |
| |
| exponent += (sign == '-' ? -num : num); |
| } |
| |
| if (!allow_trailing_junk && |
| AdvanceToNonspace(unicode_cache, ¤t, end)) { |
| return JunkStringValue(); |
| } |
| |
| parsing_done: |
| exponent += insignificant_digits; |
| |
| if (octal) { |
| return InternalStringToIntDouble<3>(unicode_cache, |
| buffer, |
| buffer + buffer_pos, |
| sign == NEGATIVE, |
| allow_trailing_junk); |
| } |
| |
| if (nonzero_digit_dropped) { |
| buffer[buffer_pos++] = '1'; |
| exponent--; |
| } |
| |
| ASSERT(buffer_pos < kBufferSize); |
| buffer[buffer_pos] = '\0'; |
| |
| double converted = Strtod(Vector<const char>(buffer, buffer_pos), exponent); |
| return (sign == NEGATIVE) ? -converted : converted; |
| } |
| |
| } } // namespace v8::internal |
| |
| #endif // V8_CONVERSIONS_INL_H_ |